THE AMERICAN MUSEUM JOURNAL 



was a tiffanyite, besides several carbonados. The radium pre- 

 parations used were of the highest activity obtainable, and were 

 secured for the Museum through the liberality of Mr. Edward 

 D. Adams. The results here announced were obtained through 

 the use of radium bromide of 300,000 and radium chloride of 

 7,000 activity, and with radium barium carbonate of 100 activity, 

 uranium being taken as the standard at i . 



Minerals may be separated tentatively into those which 



1. Do not respond to radium, ultra-violet or Roentgen rays. 



2. Respond to radium only. 



3. Respond to ultra-violet rays only. 



4. Respond to Roentgen rays only. 



5 . Respond to radium and ultra-violet rays (not to Roentgen 



rays) . 



6. Respond to radium and Roentgen rays (not to ultra-violet 



rays) . 



7. Respond to ultra-violet and Roentgen rays (not to radium) . 



8. Respond to radium, ultra-violet rays and Roentgen rays. 



With ultra-violet rays it was found that minerals from Lang- 

 ban, Sweden, behave differently from the same species from 

 other localities. The obvious suggestion is that here, and at 

 points where similar exceptional results appear, as at Borax 

 Lake, there is present some rare (perhaps new) element, widely 

 diffused in very minute quantities. An illustration is given by 

 the behavior of glauberite; specimens from Borax Lake, Cali- 

 fornia, Laramie and Spain phosphoresce, while specimens from 

 Chile do not. 



It is noteworthy that tourmaline, which is so markedly 

 pyroelectric, gives no response; nor does beryl, save in three 

 specimens from Haddam Neck, Conn. American sapphires of 

 various kinds, spinel, chrysoberyl and almost all jades, gave 

 no response to the ultra-violet rays. Most of the gem-minerals, 

 except diamond, opal and kunzite, are little acted upon. 



The studies indicate the presence with the zinc in willemite 

 and hydrozincite and in the artificial phosphorescent zinc sulphide 

 and zinc oxide, of some element, probably not yet determined, 

 that possesses peculiar properties, one that in combination with 



